Separation of hollow heart potato tubers by means of size grading, specific gravity, and x-ray examination

Summary

• 1. A total of 1,146 pounds (3,443 tubers) of Irish Cobbler potatoes grown in the Red River Valley were graded into six size classes and into six specific gravity classes and the incidence of hollow heart in each size and specific gravity class was determined.

• 2. The percentage by weight of hollow heart in each size class ranged from zero in the tubers smaller than 1.5 inches in diameter to 78.0 for tubers larger than 3.5 inches in diameter. However, of the 24.3 per cent hollow heart present in the entire 1,146 pounds examined, 20.8 per cent occurred in the size range 2.0 to 3.5 inches, whereas the remaining 3.5 per cent occurred in the potatoes larger and smaller in size.

• 3. The hollow heart in each specific gravity class ranged from 86.1 per cent in the potatoes having a specific gravity of 1.06 and below to 5.3 per cent in the potatoes having a specific gravity above 1.10. However, in order to reduce the hollow heart incidence to a level below the maximum tolerance allowable (5 per cent) for U. S. No. 1 potatoes, it would be necessary to grade out all tubers having a specific gravity lower than 1.10, or approximately 52 per cent of the crop.

• 4. The X-ray examination of 1,441 tubers of Irish Cobbler, 1,625 tubers of selection No. 6.39-4-40, and 1,270 tubers of Early Ohio potatoes in 1944 resulted in the detection of 74.6 per cent, 83.1 per cent, and 84.1 per cent, respectively, of the hollow heart present in these varieties. The total hollow heart present in the 695 pounds of tubers examined was reduced from 12.9 per cent to 2.7 per cent through the use of this method of detection.